Are Fermented Vegetables Good for Pets?

Written by Dr. Karen Shaw Becker
safe for pets
dog and cat with fermented vegetables

Story at-a-glance -

  • Fermented vegetables offer nutritive and probiotic effects for both dogs and cats, and may help optimize digestion
  • Fermented vegetables may also help improve cognitive and gastrointestinal health, and immune function
  • Slowly build up your pet's tolerance to fermented vegetables to avoid stomach upset, feeding up to only 1 to 3 teaspoons per 20 pounds of their body weight

Fermented vegetables are a good example of human-grade fresh foods that are easy to digest and contain concentrated amounts of nutrients that your pets will benefit from. Here's how you can safely add fermented vegetables to whatever your pet is eating and how you can build up their tolerance, immunity and gut health over time.

What Are Fermented Vegetables and Where Did They Come From?

Because of the increasing information and research surrounding the importance of gut health, fermented foods have gone from obscurity to being a staple in diets.1 These foods have been around for centuries, from Korea's kimchi to Indonesia's tempeh.2,3

Fermentation first started as a form of preservation for fresh vegetables, fruits and meat, but it was eventually found that this process acted as a multiplier for nutritive value and as a source of beneficial bacteria. Thanks to the fermentation process, the nutrition level of some of the most common foods, including vegetables, is drastically increased. This has led to multiple studies looking at the effects of fermented vegetables on gut health, immune system health and even cognitive health.4

Putting the Spotlight on Sauerkraut

Germany map

One popular type of fermented vegetable is sauerkraut, or fermented cabbage. It's widely popular in Germany, but did you know that it actually hailed from ancient China? When the Great Wall was being constructed, the workers lived on rice and cabbage, and in the winter they added rice wine to the vegetable to preserve it — thus creating the tangy side dish many people love today.5

China map

What's even better is that these benefits are not limited to humans, but may also include our companion animals. While healthy raw vegetables are a great addition to any dog or cat's diet, fermented vegetables may supercharge digestion and boost healthy gut bacteria, which is vital for promoting immune health.6 They offer vitamins B and K2, choline and acetylcholine, which are produced or increased during the fermentation process.

The fermentation process also increases the amount of vitamin C in the foods, as documented in a 2014 research from the Nigerian Food Journal. A significant increase in vitamin C, together with flavonoid and phenolic content, was observed in fermented okra seeds.7 This has also been documented in a 2008 study from Food Chemistry, wherein white cabbage had significant increases in antioxidant levels after fermentation.8

Serving fermented vegetables in addition to a pet's daily food can be good for your pet and may boost their nutritional intake for each meal. However, remember that all "extras" should comprise less than 10% of your pet's daily caloric intake.

Improve Your Pet's Brain Health With Fermented Vegetables

Numerous studies have shown the connection between the gut and the brain, including the production of serotonin — a neurotransmitter that is produced in the digestive tract.9,10 However, the effects of fermented food on the brain lie in the neuroprotective properties they possess.11

A 2016 review from Preventive Nutrition and Food Science discusses that fermented fruits and vegetables have free radical-scavenging and antioxidant properties, which may help stop neurotoxicity and inhibit memory deficits.12 A 2014 study from the Journal of Physiological Anthropology also showed that fermented foods influence mental health and mood through their effects on the microbiota, GABA production and the reduction of intestinal permeability.13

Fermented Vegetables May Help Improve Gut Health

Fermenting vegetables makes them easier to digest due to the pre-digestion effect brought on by the components produced during the process. Eating fermented foods will also help inhibit the production of anti-nutritional factors, such as trypsin inhibitor, which lowers nutrient absorption. The probiotic effect of fermented foods helps improve digestion and nutrient assimilation.14 Due to the fermentation process, the nutrients in fermented vegetables can be better utilized by your pet's body.15

did you know

Did You Know?

fermented vegetable

Each bite of fermented food your pet consumes provides trillions of beneficial bacteria — far more than what probiotic supplements can provide. Probiotic supplements provide only billions of colony-forming bacteria.16

Stronger, More Resilient Immune System for Your Pets

Maintaining a healthy gut microbiota is closely tied to immune health as the majority of the immune system resides in the gut and tonsils.17 Fermented foods contain numerous microbial metabolites responsible for biological functions, including the production of bio-regulating peptides, which may exhibit immuno-stimulatory activities.18

Fermentation Helps Improve Nutrient Bioavailability

Fruits and vegetables are inherently rich in vitamins and minerals, as well as phytochemicals such as flavonoids and phenolic compounds. The fermentation process helps improve the bioavailability and bioaccessibility of these nutrients through lactic acid. According to a 2017 study from Food Research International, lactic acid bacteria fermentation generates bioactive peptides and short chain fatty acids, converts molecules with added biological value, and at the same time lowers the sugar content.19

Here's How to Give Your Pets Fermented Vegetables

"When giving your pets fermented vegetables, remember to build up their tolerance gradually."

To start, you can add half a teaspoon to their regular food and slowly increase the amount. This will help them build up their tolerance to the new food and avoid unnecessary stomach upset. Ideally, pets can tolerate 1 to 3 teaspoons of fermented vegetables per 20 pounds of body weight.

However, because of the tangy smell and taste of fermented vegetables, some dogs and many cats may not be too keen on eating them. You can try feeding them tiny amounts first and see if they change their mind. If not, do not force them. Just opt for high-quality probiotic supplements instead.

Myths About Fermented Foods

Because of the unique flavor and texture of some fermented foods, myths and misconceptions have plagued their existence. Some of the most common misconceptions include:

  • Fermented food is rotten food — Because of the distinct acidic aroma and flavor of some fermented foods, some people mistake it as a sign that these are rotten. However, what you are smelling is largely caused by lactic acid, produced from the breakdown of sugars and starches during the fermentation process. This lactic acid preserves the food by halting the growth of bad bacteria.20
  • Fermented foods can mess with your pet's digestion — Intolerance to fermented foods may lead to diarrhea and stomach upset, especially when trying it for the first time. The secret is to build up tolerance to it, starting with small amounts.

    In fact, Tim Spector, a professor of genetic epidemiology at King's College London, recommends eating fermented food in small amounts frequently to "energize" your gut microbiota. Once your digestive system starts to familiarize itself with fermented foods, the benefits will surely outweigh any initial stomach upset.21

did you know

Fun Fact About Fermented Vegetables


In 2008, the first-ever Korean astronaut was set to go to space — warranting three national institutes to start developing "space kimchi," or kimchi that can be brought to space without either going bad or losing its distinct flavor and taste.

Unfortunately, the institutes needed to remove all the microbes — together with all the health benefits — to ensure that kimchi wouldn't explode all over the equipment during space travel.22

Fermented Vegetables Are Good for Pets, but in Moderation

Misinformation about many healthy fruits, vegetables, nuts and seeds abounds on the internet. This is because websites have labeled all risks (such as the risk of over-consumption causing gastrointestinal issues, or choking on too large of pieces or pits) as "toxicities," which isn't true, but has managed to confuse millions of pet lovers, nonetheless.

Fermented vegetables are safe for both dogs and cats (if they'll eat them) and may even provide benefits such as better immunity and cognitive health,23,24 thanks to their probiotic effects. However, moderation is crucial especially if it's your first time feeding your pet fermented foods.

If animals have histamine sensitivities, fermented foods may exacerbate their symptoms and may best be avoided. Make sure that you work up your dog's and cat's tolerance first to avoid stomach upset; pets can eat up to 3 teaspoons of fermented vegetables for every 20 pounds of your pet's weight. You can add fermented vegetables to whatever your pet is currently eating.